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Airway Adjuncts, Emergency Medicine

Basics

Description

- Airway adjuncts are devices used for management of the upper airway - Often used as rescue techniques/devices when unable to intubate with standard techniques and difficult to mask ventilate - Oral and nasopharyngeal airways: - Lift tongue off hypopharynx - Combined with positioning aid in airway patency - Nasopharyngeal airway may be used when gag reflex intact - Oropharyngeal airway placement requires absent gag reflex

- Extraglottic devices (EGD): - Supraglottic (SGD) class (i.e., LMA, PAXpress, CobraPLA, iGel, etc.) - These sit above and surround the glottis - Retroglottic (RGD) or infraglottic (IGD) class (i.e., Combitube, King tube, Ruch EasyTube, etc.) - RGD/IGD ventilate at the hypopharynx and occlude the esophagus

- Predictors of difficult to bag-mask ventilate (MOANS) - M - Mask seal (beards/structural abnormality) - O - Obese or obstructed - A - Advanced age (>55 yr) - N - No teeth - S - Stiff

- Predictors of difficult laryngoscopy and intubation (LEMON) - L - Look externally - Micrognathia - Buck teeth - Large tongue - Short neck

- E - Evaluate 3-3-2 - Mouth opens <3 fingerbreadths - Horizontal length of mandible <3 fingerbreadths - Thyromental distance <2 fingerbreadths

- M - Mallampati score (increasing difficulty) - Class I: Soft palate, uvula, fauces, pillars visible - Class II: Soft palate, uvula, fauces visible - Class III: Soft palate visible - Class IV: Hard palate only visible

- O - Obstruction - Vocal changes/muffled voice - Difficulty managing secretions - Stridor

- Predictors of difficult cricothyrotomy (SHORT) - S - Surgery or disrupted airway - H - Hematoma or infection - O - Obese (access problem) - R - Radiation - T - Tumor

- Rapid sequence intubation - Prepare - Suction, BVM, ETT, primary airway management modality, rescue airway management modality, medications

- Pretreatment - Minimize adverse responses to airway management - Suspected elevated ICP - Ischemic heart disease or major vessel dissection/rupture - Adults with significant reactive airways disease - Children up to 10 yr of age

- Positioning - Head extension - Cricoid pressure (Sellick maneuver)

- Placement of tube - Postintubation - Confirm ETT placement - Sedation with benzodiazepines, opiates, propofol, or other agents - Continued paralysis as needed combined with adequate sedation

- Induction - Etomidate: 0.3 mg/kg IV - Ketamine: 1-2 mg/kg IV or 4-7 mg/kg IM - Midazolam: 0.07-0.3 mg/kg IV - Propofol: 2-2.5 mg/kg IV - Thiopental: 3 mg/kg IV

- Paralysis - Succinylcholine: 1-1.5 mg/kg (peds: 2 mg/kg) IV, 2.5 mg/kg IM/SC - Rocuronium: 1 mg/kg IV (paralyzing dose); 0.1 mg/kg IV (defasciculating dose) - Pancuronium: 0.1 mg/kg IV (paralyzing dose); 0.01 mg/kg IV (defasciculating dose) - Vecuronium: 0.1 mg/kg IV (paralyzing dose); 0.01 mg/kg IV (defasciculating dose)

  • Airway adjuncts are devices used for management of the upper airway
  • Often used as rescue techniques/devices when unable to intubate with standard techniques and difficult to mask ventilate
  • Oral and nasopharyngeal airways:Lift tongue off hypopharynxCombined with positioning aid in airway patencyNasopharyngeal airway may be used when gag reflex intactOropharyngeal airway placement requires absent gag reflex
  • Extraglottic devices (EGD):Supraglottic (SGD) class (i.e., LMA, PAXpress, CobraPLA, iGel, etc.)These sit above and surround the glottisRetroglottic (RGD) or infraglottic (IGD) class (i.e., Combitube, King tube, Ruch EasyTube, etc.)RGD/IGD ventilate at the hypopharynx and occlude the esophagus
  • Blind insertion technique (specific to device)
  • Less protection from aspiration compared to ET tube
  • High success rates for placement of EGDs

Epidemiology

  • 95% success with 1st method of airway management
  • 98% overall success of intubation
  • 4% of ED airways are difficult

Diagnosis

Signs and Symptoms

Physical Exam

  • Predictors of difficult to bag-mask ventilate (MOANS)M - Mask seal (beards/structural abnormality)O - Obese or obstructedA - Advanced age (>55 yr)N - No teethS - Stiff
  • Predictors of difficult laryngoscopy and intubation (LEMON)L - Look externallyMicrognathiaBuck teethLarge tongueShort neckE - Evaluate 3-3-2Mouth opens <3 fingerbreadthsHorizontal length of mandible <3 fingerbreadthsThyromental distance <2 fingerbreadthsM - Mallampati score (increasing difficulty)Class I: Soft palate, uvula, fauces, pillars visibleClass II: Soft palate, uvula, fauces visibleClass III: Soft palate visibleClass IV: Hard palate only visibleO - ObstructionVocal changes/muffled voiceDifficulty managing secretionsStridorN - Neck mobility (limited)
  • Predictors of difficult cricothyrotomy (SHORT)S - Surgery or disrupted airwayH - Hematoma or infectionO - Obese (access problem)R - RadiationT - Tumor
  • Predictors of difficult EGD (RODS)R - Restricted mouth openingO - ObstructionD - Disrupted or distorted airway anatomyS - Stiff lungs or cervical spine

Diagnosis Tests & Interpretation

  • Pulse oximetry should rise or remain at high level with successful airway management
  • Confirming correct placement:
  • Fiberoptic bronchoscopy (gold standard)
  • End tidal capnometry/capnography (>99% reliable)
  • Physical exam (common but unreliable)
  • Chest rise/fall
  • Auscultation of breath sounds with absence of sound over epigastrium
  • Condensation inside the ETT
  • Arterial blood gas is used to guide ventilator settings once airway established.

Imaging

CXR: Useful only in patients following endotracheal intubation to exclude mainstem bronchus intubation or pneumothorax and to adjust the position of the tube

CXR does not rule out esophageal intubation

Treatment

Pre-Hospital

  • Options for patients requiring prehospital airway management vary by region and include:Bag-valve-mask ventilation ± OPA or NPAOrotracheal intubation ( ±RSI)Nasotracheal intubationEGD placementSurgical airway

Initial Stabilization/Therapy

  • Maintain in-line cervical spine immobilization in trauma patients
  • Oxygen (high flow via nonrebreather or BVM)
  • Vascular access (for resuscitation and medication administration) IV or IO

Ed Treatment/Procedures

  • Rapid sequence intubation
  • PrepareSuction, BVM, ETT, primary airway management modality, rescue airway management modality, medications
  • PreoxygenateNRB or BVM with 100% FiO2 for 3 min
  • PretreatmentMinimize adverse responses to airway managementSuspected elevated ICPIschemic heart disease or major vessel dissection/ruptureAdults with significant reactive airways diseaseChildren up to 10 yr of age
  • Paralysis with inductionAdministration of induction agentRapid sequential administration of paralytic agent

Paralysis is relatively contraindicated in anticipated difficult airway

  • PositioningHead extensionCricoid pressure (Sellick maneuver)
  • Placement of tube
  • PostintubationConfirm ETT placementSedation with benzodiazepines, opiates, propofol, or other agentsContinued paralysis as needed combined with adequate sedation
  • Failed intubation
  • Consider other intubation techniques in failed airway algorithm or use of airway adjunct
  • Surgical airway as last resort

Medication

  • InductionEtomidate: 0.3 mg/kg IVKetamine: 1-2 mg/kg IV or 4-7 mg/kg IMMidazolam: 0.07-0.3 mg/kg IVPropofol: 2-2.5 mg/kg IVThiopental: 3 mg/kg IV
  • ParalysisSuccinylcholine: 1-1.5 mg/kg (peds: 2 mg/kg) IV, 2.5 mg/kg IM/SCRocuronium: 1 mg/kg IV (paralyzing dose); 0.1 mg/kg IV (defasciculating dose)Pancuronium: 0.1 mg/kg IV (paralyzing dose); 0.01 mg/kg IV (defasciculating dose)Vecuronium: 0.1 mg/kg IV (paralyzing dose); 0.01 mg/kg IV (defasciculating dose)

Follow-Up

Disposition

Admission Criteria

Almost all intubated patients should be admitted to an ICU or OR

Discharge Criteria

Rarely, ED patients who have been intubated may be extubated in the ED and discharged after a period of observation.

Pearls and Pitfalls

  • Failure to ventilate is a life-threatening condition
  • Assess every patient for the possibility of difficult mask ventilation or intubation
  • Always formulate a back-up plan in case of a failed attempt
  • Do not fixate on intubation but rather successful ventilation and oxygenation
  • Move to alternate airway management techniques and consider surgical airway if unable to intubate or ventilate despite use of airway adjuncts
  • Oro- and nasopharyngeal airways are available in infant+ sizes
  • LMAs are available in infant+ sizes
  • Combitube is only designed for patients >48 in in height
  • Nasotracheal intubation is contraindicated in children under 10 yr of age

Additional Reading

  • Murphy MF. Airway management. In: Wolfson AB, Hendey G, Ling L, et al., eds. Harwood-Nuss' Clinical Practice of Emergency Medicine. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2009.
  • Walls RM (ed). Manual of Emergency Airway Management. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2012

Codes

ICD9

  • 96.01 Insertion of nasopharyngeal airway
  • 96.02 Insertion of oropharyngeal airway
  • 96.05 Other intubation of respiratory tract

ICD10

0CHY7BZ Insertion of Airway into Mouth and Throat, Via Natural or Artificial Opening

SNOMED

  • 426153007 insertion of artificial airway (procedure)
  • 7443007 insertion of oropharyngeal airway (procedure)
  • 182692007 nasopharyngeal airway insertion (procedure)